The performance of integrated electronics chips has increased dramatically over recent years. This increased performance has been achieved in part by increasing the chip operating frequency which has resulted in greater chip power (Watts) and chip power density (Watts/cm2). This has increased the need for efficient thermal power management to conduct the heat away from the chip to the ambient surroundings using for example heat sinks, fans, vapor chambers, liquid coolers and other means to cool the chips to maintain an acceptable operating temperature. Today's powerful processors generate so much heat that chips will thermally overheat if the thermal cooling solution is not operational even for a short period of time. A heatsink is a device that is attached to the microprocessor chip to keep it from overheating by providing a thermal conduction path of the heat generated by the chip to the ambient environment by moving air over the heat sink. Basic heat sink structures have a heat spreader which makes thermal contact with the chip via an interface of a thermally conductive adhesive and fins which provide a large surface area to transfer the heat to the ambient air environment. Typically a fan is used to provide an air flow over the fins to optimize the heat transfer from the heat sink to the ambient air.
Most commercially available computers incorporate a heat sink directly attached to the chip. This combination of the chip and heat sink is often referred to as a “chip package.” The basic design of a chip package is shown in FIG. 1 in which a heatsink 102 is mounted on a chip 120. The heatsink 102 shown is a conventional passive metal heat sink with fins. The chip 120 makes thermal contact with the heat sink 102 through a thermal interface material 111. The chip 120 is attached to a chip carrier 122 which has a pin grid array and interfaces to an electrical socket 110 which is mounted onto a printed circuit board 125. The heat sink 102 is secured to the chip 120 by a frame 112 and mounting screws 116 in order to inhibit horizontal and vertical movement of the heat sink as would occur under external forces, including shock and vibration of the system. FIG. 2 shows the top view of the chip package of FIG. 1.
Clearly this design is meant to stabilize and constrain the heatsink 102 and it is effective in doing so. The problem inherent in this design, however, is that the rigid assembly results in deformation of the entire package due to differences in the coefficient of thermal expansion (CTE) between the heatsink 102 and the chip package assembly. The need to constrain the mechanical motion of the heat sink 102 due to external forces (shocks) requires a rigid, non-compliant attachment which unfortunately results in package deformation. Contributing to this problem is the rigidity and non-compliance inherent in heatsinks, which are usually metal structures. Currently produced heatsinks fail to provide for the structural stresses and strains generated during the operation of the electronic device (the chip 120). Therefore, there is a need for a solution that overcomes the above shortcomings of the prior art.